Six people with experience in human resources rated the Facebook pages of 518 college students in terms of the "Big Five" personality traits of modern psychology: neuroticism, extroversion, openness to experience, agreeableness, conscientiousness.

"The results reveal… that evaluators can reach independent agreement as to personality-related phenomena posted on Facebook. The results also show that the evaluators exhibited an acceptable degree of internal consistency reliability. Together, these results suggest that evaluators trained to assess participant profiles can provide reasonably reliable estimates of Big Five personality traits from [social networking websites]."

The ratings of evaluators correlated strongly with participants' self-rated personality traits as well as with job performance, hirability and academic performance.

Researchers stated that the study corroborates earlier evidence that people externalize personality tendencies to their environments partly through the expressive mechanisms of identity claims and behavioral residue.

Although the practice is common among employers, there are obvious legal and ethical concerns. Interviewers usually avoid questions regarding race, religion, sexual preference or marital status because of potential legal issues, but such information may be clearly posted on someone's profile. Collecting this non-job-relevant information could result in biased hiring decisions.

Nevertheless, the researchers concluded that analyzing social networking profiles is useful for screening applicants as it is less time-consuming– the average assessment took 5 to 10 minutes and did not require a respondent's presence– and more cost-effective than traditional methods.

And best of all for potential employers, the practice is particularly accurate:

"Observer ratings of personality traits via [social networking websites] are roughly as accurate as ratings made by individuals who have detailed knowledge of the ratee, such as their significant others and close friends."